Lubricant for processing metals



Patented May 13, 1947 amaze LUBRICANT roa raoosssnvo METALS JosephBarrel Shipp, Wilmington, Del, and Osborne Coster Bacon and Charles J.Pedersen, Penna Grove, N. J., assignors to E. I. du Pont de Nemours &Company,- Wilmington, DeL, a

corporation of Delaware No Drawing. Application June 1, 1945,

Serial No. 597.154

2 Claims.

This invention relates to new compositions of matter and particularly toaqueous emulsions especially adapted for lubricating metals durinprocessing operations, such as cutting. drawilnig, drilling, tapping,milling, stamping and the For many years there has been a problem ofimproving lubricants used in cutting and drawing metals and in variousother metal processing steps. In many cutting operations, such as thoseperformed on lathes, drill presses and milling machines, it is verydifilcult to keep a lubricant at the cutting point due to the continualflow of metal past this point under extreme pressures. The ideallubricant would be one which could be applied to the cutting edge beforecutting was begun, and which would cling tenaciously to that edge andfacilitate the sliding of the metal surfaces by the cutting edge.Without proper lubrication at the cutting edge, there is a tendency formetal to build up on the cutting tool and this impairs cutting.Likewise, in other metal cutting operations where high pressures areinvolved, there is a. tendency for metal to metal contact betweencutting tool or die and metal being processed, unless a tenaciouslubricant is used. As a result, there is a welding of the two metalswhich eventually causes scoring or tearing out of metal, giving a. roughsurface to the object being processed. This problem exists in cutting,drawing, stamping and other operations.

In the cutting of soft metals, the difliculty is accentuated due to thelow resistance of the metals to deformation underpressure. Thus, intapping holes in aluminum, there is a tendenc to tear out the metal andgive an over size hole unless a highly eflicient lubricant is used. Dueto this fact, it was difflcult to get close fitting threads in aluminum.It has been customary to use under-size taps in tapping aluminum andother soft metals. This necessitates two sets of taps where one set oftaps would be suflicient if a satisfactory lubricant were used. Intapping hard metals to give close clearance threads, there metalprocessing operations, such as cutting.

drawing, drilling, tapping, milling, stamping and the like. However,such emulsions tend to foam to an objectionable extent during handling,dilution and in use.

The emulsions of Shipp and Pedersen are disclosed in detail and areclaimed in their copending application Serial No. 596,078, flied May 26,

1945. A brief description of such emulsions folpresence of ahydrogenation catalyst until the major proportion, at least of thecarboxyl groups have been reduced, followed by separation of thehydrogenation catalyst and distillation of the reaction mixture toremove substantially all alcohols up through octadecyl alcohol. Theresidue left in the still is a Lorol residue. It is a product ofindeterminate composition and appears to contain higher alcohols, estersof higher alcohols, ethers of higher alcohols, hydrocarbons, glycerineand esters of glycerine with the ethers of the higher alcoholspredominating. Frequently, it is desirable to subject this residue to afurther hydrogenation and distillation so as to recover more of thevaluable alcohols and to reduce the proportion of esters in the residue.

The water-soluble non-acidic salts of the acidesters of phosphoric acidwhich are surface-active, that is, which have emulsifying properties,are particularly effective for emulsifying "Lorol residues in water toproduce non-corrosive, nonrusting and non-discoloring emulsions. Anacidester" of phosphoric acid is one in which from 1 to 2 of thehydrogens of phosphoric acid has been replaced by an esterifying groupand which contains from 1 to 2 unreplaced hydrogen atoms. Theesterifying group may be any organic group which imparts substantialsurface activity to the compound. Suitable esterifyin groups arelong-chain alkyl, alkyl substituted aryl, aralkyl and the like. By"long-chain alkyl, is meant open-chain aliphatic hydrocarbon groupsof 8or more carbon atoms. Preferably, the long-chain alkyl groups willcontain from 8 to 20 carbon atoms. Representative long-chain al ylgroups are octyl, decyl, dodecyl, tetradecyl, hexadecyl and cetyl.Preferably, the acid-esters will be mixtures of mono and di-esterscontaining about 1.5 esterifying groups for each phosphate radical. Bestresults have been obtained with acid-esters containing about 1.5long-chain alkyl groups of 8 to 18 carbon atoms per phosphate radical.

The salts of the acid-esters are those in which the ester hasbeencompletely neutralized by abasic salt-forming substance which forms,with the ester, a surface-active water-soluble salt. Suitable basicsalt-forming substances include primary, secondary and tertiary amines,particularly mono-, diand trialkylamines and alkylolamines. Preferably,the basic saltforming substance will be a short-chain aliphatic amineand particularly, an alkylolamine, such as triethanolamine. f

The concentration of the "Lorol" residue in the emulsion may be widelyvaried in accordance with the use towhich it is to b put. Where theemulsion is to be employed as a coolant.- as well as a lubricant, andapplied by a circulating pump or the like. the Lorol" residue should bepresent in a concentration of from about 1% to about and preferably fromabout 2% to about 4%.

' Where the lubricantis to be applied to the work the and that the pineoil. white camphor oil.

"Tetralin.' and "Hexalin are very eflective to inhibit the tendency ofthe emulsions to foam.

"Tetra1in is the trade name for tetrahydronaphthalene and fHexalin" isthe trade name for cyclohexanoL Ordinarily, we employ from about 25% toabout 100% of the anti-foaming agent, based on the weight of the Lorol"residue. Usually, about'25% to about 50% of the anti-foaming age t,based on the "Lorol" residue, will be sufficient and preferred. However,larger or smaller amounts of anti-foaming agent .may be employed as theamount will be largely dependent upon the concentration of effectivenessof the emulsifying agent. Increasing amounts of emulsifying agent willgenerally require larger amounts of the antifoaming agent. 4

Representative concentrated preparations, which have been employedsatisfactorily in commercial applications, had the following compositostir into water to obtain the desired diluted emulsion for use.

The proportion of the emulsifying agent in the emulsion may be widelyvaried and will be largely dependent upon the effectiveness thereof asan emulsifying agent. For practical purposes, sufficient emulsifyingagent should be used to provide a stable emulsion. A substantialincrease of the emulsifying agent over that required to provide a stableemulsion will usually be undesirable because it increases the tendencyof the emulsion to foam during use. Proportions of emulsifying agentranging from as little as 2% to as much as 50% based on the "Lorolresidue have been employed satisfactorily. With the preferredemulsifying agents, very satisfactory results have been obtainedemploying from about 3% to about 10% of the emulsifying agent based onthe "Lorol residue.

It is an object of the present invention to provide new and usefulemulsions. Another object is to provide novel emulsions particularladapted for lubricating metals during metal processing operations andwhose tendency to foam have been largely inhibited. Still another objectis to provide improved metal processing lubricants, and particularlylubricants which are stabl and non-corrosive toward metals and which aresubstantially non-foaming. Other objects are to provide new compositionsof matter and to advance the art. Still other objects will appearhereinafter.

The above and other objects may be accom plished in accordance with ourinvention which comprises providing an aqueous emulsion of a "Lorol"residue, in which the emulsifying agent is a surface-activewater-soluble non-acetic salt of an acid-ester of phosphoric acid. towhich has been added a member of the group of pine oil, white camphoroil, Tetralin" and Hexalin" in an amount suflicient to substantiallyinhibit the tendency of the emulsion to 0am. We have found that suchemulsions are eflective lubricants for metal processing operations, suchas cutting.. wi drilling, tap in i i s. stamping and .tions:

Parts Parts Lorol" Residue 40 40 iisfi h t. 0' 1? 8% osp a'Iriethgnolamine 0. 75 l. 6 my I 46.60 45.00

ngihis is a mixtuie of lelsisrs ofi hosfiholriolacidlkcgiitaininglobflutj I! ll 08 0 (2&0 re 08 66 ll 9- rived m per ure g! primarystraight-chain aliph ic i ilcgho of 8 to 14 carbon atoms.

In order to more clearly illustrate our invention, the preferred modesof carrying the same into effect and advantageous results to be obtainedthereby, the following examples are given.

Example 1 1 Forty lbs. of residue, left in the still after distilling ahydrogenated cocoanut oil, hydrogenated according to U. S. Patent2,023,383, was mixed with 10 lbs. of pine oil and then emulsified with50 lbs. of a 5% aqueous solution of the triethanolam'ine salt of a mixeddodecyl and decyl phosphate by stirring with a high speed stirrer. Thephosphate was prepared from a mixture of equal parts of dodecyl anddecylialcohols and contained about 1.5 alkyl groups per phosphateradical. The resulting emulsion was diluted with 10 parts of water for 1part of emulsion, and the diluted emulsion used as a coolant andlubricant indrawing dynamite blasting caps from aluminum stampings.These dynamite caps were extremely thin walled and yet there was noindication of tearing or scoring when the above lubricant was used. Withordinary lubricants, it had been noted that a large number of caps hadtorn edges and scored surfaces. It was also noted that, with thelubricant prepared according to this invention, the life of the dies wasgreatly increased. Similar blasting caps were drawn from gliding metal,which is a high copper content alloy, and an equal improvement was notedover the use of other lubricants. There was no corrosion of the brightsurface of either the aluminum or the gliding metal, even when thelubricant was left in contact with the metal for several hours. The pineoil effectively inhibited foaming of the emulsion during use.

Example 2 air. a

was

threaded with the same die, but using asulfurized cutting oil aslubricant. Likewise, a one inch 1 hole was tapped in a highcarbon steel,using the emulsion of Example 1 as lubricant. After tapping, the metalwas cut through the holeand the threads viewed under ten-powermagnification. Again it was observed that a very smooth.

out had been obtained.

' Example 3 Twenty pounds of pine oil were added to 40 lbs. of theresidue from the distillation of hydrogenated cotton seed oil. The pineoil and residue were heated to 60 C. and poured with violent stirringinto 50 lbs. of water containing 4% of the salt of 2-amino 2-methylpropanol-l and decyl,

phosphoric acid in which 1V2 alkyl groups are present for eachphosphoric acid unit. This in aluminum alloy crank cases. With thislubricant, very clean cut threads were obtained using standard size tapsand a'close fit was also obtained as shown by the "Go-No Go" gauge. A

similar emulsion, except that the pine oil was omitted, foamed to anobjectionable degree but the foaming was overcome by the addition of thepine oil.

Example 4 Seven and one-half pounds of a mixture of mono and di-laurylphosphates, containing about 1.5 lauryl groups per phosphate radical,,was added to 27 poundsof water. Seven and onehalf pounds oftriethanolamine was added and the solution heated to 60 C. Eighteenpounds of Tetralin" was added to forty pounds of a Lorol" residueobtained from cocoanut oil and this mixture heated to 60 C. The Lorolresidue-"Tetralin" solution was then added to the aqueous solution ,withvigorous stirring. A creamy emulsion was obtained which could be readilydiluted with water. One pound of this emulsion was diluted with fifteenpounds of water and placed in a circulating system of a pipe threadingmachine. This machine was used for threading various size iron pipes.Microscopic examination of the cut surfaces of the threads showed a muchsmoother out than had previously been obtained with a mineral oillubricant. The

tool life of the dies was also increased over that that many variationsand modifications can be made without departing from the spirit or scopeT of invention. For example, "Lorol" residues may be prepared from othervegetable oils an animal oils. Also. other salts of other acid-esters ofphosphoric acid, which are emulsifying agents,

. may be substituted for those specifically mentioned.-

We claim: v 1. An aqueous emulsion of a distillation residue derivedfrom ahydrogenated natural fatty oil by distilling 01! fractions upthrough; octadecyl alcohol; in which the emulsifying; agent is asurface-active-water -soluble non-acidic 'salt of a long-chain alkylacid-ester of' plu'iiipliioricv acid, the distillation residue beingpresentin'a concentration of from about 1% tolabout 70% and theemulsifying agent being. present in .a minor proportion suflicient toforms substantially stable emulsion; said emulsion Having Ten-aim"incorporated therein in an augmentto substantially inhibit foamingiiu'ruse. emulsion was diluted vwith 20 parts of water and used as acoolant and lubricant for tapping holes 12. An auueous emulsion of adistillation resisurface-active water-soluble mixture of nonacidictriethanolamine salts of long-chain alkyl esters of phosphoric acidcontaining about 1.5 alkyl groups per phosphate radical, thedistillation residue being present in a concentration of from about 1%to about 70% and the emulsifying agent being present in a minorproportion sumcient to form a substantially stable emulsion, saidemusionhaving Tetralin incorporated therein in an amount sumcient tosubstantially inhibit foaming during use.-

JOSEPH HARREL SHIPP. OSBORNE COSTER. BACON. CHARLES J. PEDERSEN.

REFERENCES CITED I The following references are of record in the file ofthis patent:

UNI'I'EHD STATES PATENTS Number Name Date 1,617,077 Nill Feb. 8, 19271,717,939 Rolfsen June 18, 1929 1,947,725 Macarthur Feb. 20, 19342,023,383 Schrauth' Dec. 3; 1935 2,045,551 Iddings June 23, 19362,291,066 Waugh July 28, 1942 OTHER nnrnamrcns Chem. and Eng. News,April 25, 1943, page 561. (Copy in Div. 64.)

Websters New International Dictionary, G. and C. Merriam, Springfield.Mass. 1941. (CODY in Div. 64.)

' Patent No. 2,426,329.

" same may conform to the recordjof the casein the Patent Oflice.

' 'Sig'ned end sealed this 1st day of July, A. 1 19 47.

Certifleete of Correction JOSEPH mnnn'snlrr E-T AL.

e 67, for non-acetic that the said Letters Patent should be read withthese corrections therein that the o LESLIE r J Firct Aesz'atantUomntqeehner of It ieherehycertified thaterrors'eppear inlthepri ntedsfiicification of the above numbered patent requiring correction asfollows: Column, 3, read ngmacaklic; column 4, line 15, for ofefiectiveness read and efiectweness; and

